VTP, STP and Loops

alliasneo

Hi Everyone, hope you all had good new years.

I have been configuring some VTP/STP setups and I was just interested in something.The diagram above is what I'm working on.

The switch on the left was originally the root bridge and this topology had two ports in blocking mode. One on the bottom-middle switch going up and one on the right switch connecting to the middle. I've included the mac-addresses for these ports as well. Why were these blocking though as I thought the lowest mac-address would forward and then next on would block? I was confused on this.

Also, I have now change all of the vlan root bridges to be the top switch. but now only one port if in blocking mode. The switch on the right. would this now cause switching loops? Now that I have changed the topology over?

Thanks

alxx

Work out the priority/costs
then
you'll have which ports are designated and which are blocking

alliasneo

ahh I forgot about costs to reach the root. I was just looking at the mac address values. I need to review this subject a bit I think.

thanks